PROTECTION CIRCUIT AND GROUND FAULT CIRCUIT INTERRUPTER

• US 20160365720A1
• Filed: 01/22/2016
• Published: 12/15/2016
• Est. Priority Date: 06/11/2015
• Status: Active Grant

• Current Assignee: Ze Chen
• Original Assignee: Ze Chen
• Inventors: Pan, Xincheng, Wu, Tingting, Zhang, Ye
• Granted Patent: US 10,243,350 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02H 3/334 with means to produce an artificial unbalance for other protection or monitoring reasons or remote control H02H3/338 takes precedence
• CPC Class Codes: H02H 3/335 the main function being self testing of the device
• CPC Class Codes: H02H 3/338 also responsive to wiring error, e.g. loss of neutral, break

Abstract

The present invention relates to a protection circuit and a ground fault circuit interrupter. A protection circuit may include a power supply circuit, a ground fault detection circuit, a signal amplifying and shaping circuit, a microcontroller control circuit, a power supply detection and indicator circuit, a tripping mechanism control circuit, and a reverse grounding detection and execution circuit. The microcontroller control includes a microcontroller, a first capacitor, and a reset filter circuit. The reset filter circuit comprises a reset IC, a second capacitor, and another capacitor. A ground fault circuit interrupter may comprise an interrupter body with a protection circuit in the interrupter body. The practice of the present disclosure may address installation safety risks of conventional ground fault circuit interrupters and arc fault circuit interrupter and improve the safety of ground fault circuit interrupters.

Claims

1. A protection circuit, comprising:

a power supply circuit;

a ground fault detection circuit;

a signal amplifying and shaping circuit;

a microcontroller control circuit;

a power supply detection and indicator circuit;

a tripping mechanism control circuit; and

a reverse grounding detection and execution circuit, wherein;

the microcontroller control comprises a microcontroller, a first capacitor, and a reset filter circuit;

the reset filter circuit comprises a reset IC, a second capacitor, and a nineteenth capacitor;

a first pin of the reset IC is connected to a VCC of the protection circuit, a second pin of the reset IC is connected to a reset terminal of the microcontroller, and a third pin of the reset IC is grounded;

the second capacitor is connected between the second and third pins of the reset IC;

the first capacitor is connected between a power supply terminal of the microcontroller and a ground;

the nineteenth capacitor is connected between the first pin of the reset IC and the ground;

the power supply terminal of the microcontroller is connected to the VCC; and

a ground terminal of the microcontroller is grounded.

2. The protection circuit of claim 1, wherein:

the microcontroller control circuit carries out power-on self-test and reset for the protection circuit;

the ground fault detection circuit comprises a leakage detection circuit and a grounding detection circuit, which detect leakage failure and grounding failure, respectively;

the signal amplifying and shaping circuit comprises a leakage detection and signal amplifying circuit and a signal shaping circuit, which are connected to each other and carry out amplifying and shaping on a leakage detection signal;

the power supply detection and indicator circuit comprises a power supply detection circuit and an indicator circuit, which are connected to each other and carry out detection and displaying of a power status; and

the reverse grounding detection and execution circuit comprises a reverse connection detection control circuit and a detection and execution circuit, which are connected to each other and carry out detecting of a reverse connection of the protection circuit in a reset state and in a tripping state.

3. The protection circuit of claim 2, wherein:

the power supply circuit comprises a power supply filter circuit, a first rectifier circuit, a first filter and regulator circuit, and a second filter and regulator circuit;

the tripping mechanism control circuit comprises a reset switch, which is provided on a live line and a neutral line of the protection circuit, and a control circuit that controls the reset switch;

the first filter and regulator circuit is connected to the ground fault detection circuit;

the second filter and regulator circuit is connected to the signal amplifying and shaping circuit and the microcontroller control circuit;

the ground fault detection circuit, the signal amplifying and shaping circuit, and the microcontroller control circuit are connected in sequence; and

the microcontroller control circuit is connected to the power supply detection and indicator circuit and the tripping mechanism control circuit.

4. The protection circuit of claim 3, wherein:

the power supply filter circuit is connected to an input terminal of the live line;

a first input terminal and a second input terminal of the first rectifier circuit are respectively connected to an input terminal of the neutral line and an output terminal of the power supply filter circuit;

a first pin of the first rectifier circuit is grounded;

a second pin of the first rectifier circuit is connected to the both the first filter and regulator circuit and the second filter and regulator circuit; and

the reset switch is positioned on the live line and the neutral line after the grounding detection circuit.

5. The protection circuit according to claim 4, wherein:

the power supply filter circuit comprises an inductor coil;

the first filter and regulator circuit comprises a first resistor, a third capacitor, and an internal regulator circuit of a first pin of a leakage signal processing IC

the first resistor is connected between the second pin of the first rectifier circuit and the first pin of the leakage signal processing IC;

the third capacitor is connected between the first pin of the leakage signal processing IC and the ground;

the second filter and regulator circuit comprises a second resistor, a stabilivolt, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, a power supply IC, an eighth capacitor, a ninth capacitor, a tenth capacitor, and an eleventh capacitor;

the second resistor is connected between the second pin of the first rectifier circuit and a first pin of the power supply IC;

a positive electrode of the stabilivolt is grounded;

a negative electrode of the stabilivolt connected to first pin of the power supply IC;

the fourth, fifth, sixth, and seventh capacitors are connected in parallel between the first pin of power supply IC and the ground;

the eighth, ninth, tenth, and eleventh capacitors are connected in parallel between a second pin of the power supply IC and the ground;

the second pin of the power supply IC is connected to the VCC;

and a third pin of the power supply IC is grounded;

the leakage detection circuit comprises a first current coupling induction coil and a twelfth capacitor;

the twelfth capacitor is connected between a first terminal and a second terminal of the first current coupling induction coil;

the first and second terminals of the first current coupling induction coil are connected to the second and third pins of the leakage signal processing IC, respectively;

the live and neutral lines pass through the first current coupling induction coil;

the grounding detection circuit comprises a second current coupling induction coil and a thirteenth capacitor;

the thirteenth capacitor is connected to a first terminal and a second terminal of the second current coupling induction coil;

the first and second terminals of the second current coupling induction coil are grounded and connected to the leakage detection and signal amplifying circuit, respectively; and

the live and neutral lines pass through the second current coupling induction coil.

6. The protection circuit according to claim 5, wherein:

the leakage detection and signal amplifying circuit comprises the leakage signal processing IC, a fourteenth capacitor, a third resistor, and a fifteenth capacitor;

the fourteenth capacitor, the third resistor, and the fifteenth capacitor are sequentially connected in series between the first current coupling induction coil and the second current coupling induction coil;

the third resistor is connected between a fourth pin and a fifth pin of the leakage signal processing IC;

the signal shaping circuit comprises an internal comparison shaping pin of the microcontroller, a sixteenth capacitor, a seventeenth capacitor, a fourth resistor, a fifth resistor, a sixth resistor, an eighteenth capacitor, and a twentieth capacitor;

the sixteenth and seventeenth capacitors are connected in parallel between the ground and a sixth pin of the leakage signal processing IC;

the fourth resistor is connected between a sixth pin of the leakage signal processing IC and a control signal input terminal of the microcontroller;

the fifth and sixth resistors are sequentially connected in series between the VCC and the ground;

a connection point of the fifth and sixth resistors is connected to the internal comparison shaping terminal of the microcontroller the eighteenth capacitor and the sixth resistor are connected in parallel between the internal comparison shaping terminal of the microcontroller and the ground;

the twentieth capacitor is connected between two pins of the microcontroller and the ground;

the power supply detection circuit includes the first rectifier circuit, the first resistor, the internal regulator circuit, the third capacitor, an eighth resistor, a ninth resistor, a twenty-first capacitor, and the microcontroller;

the eighth resistor is connected between the first pin of the leakage signal processing IC and the ninth resistor, which is grounded;

a connection point of the eighth and ninth resistors is connected to a detection terminal of the microcontroller;

the twenty-first capacitor is connected between the ground and the detection terminal of the microcontroller;

the indicator circuit includes a normal signal output terminal and a fault signal output terminal of the microcontroller, a tenth resistor, an eleventh resistor, a red LED, and a green LED;

the tenth resistor is connected between the fault signal output terminal of the microcontroller and a negative electrode of the red LED;

the eleventh resistor connected between the normal signal output terminal of the microcontroller and a negative electrode of the green LED; and

a positive electrode of the red LED and a positive electrode of the green LED are connected to the VCC.

7. The protection circuit according to claim 6, wherein:

the control circuit of the tripping mechanism control circuit comprises the microcontroller, a twenty-second capacitor, a twelfth resistor, a first one-way silicon controlled rectifier, a twenty-third capacitor, a thirteenth resistor, and a relay that interfaces with the inductor coil;

the twenty-second capacitor is connected between a first triggering terminal of the microcontroller and the ground;

the twelfth resistor is connected between the first triggering terminal of the microcontroller and a control electrode of the first one-way silicon controlled rectifier;

an anode of the first one-way silicon controlled rectifier is connected to a connection point where the inductor coil is connected to the second input terminal of the first rectifier circuit;

a cathode of the first one-way silicon controlled rectifier is grounded;

the twenty-third capacitor and the thirteenth resistor are connected in series between the anode of the first one-way silicon controlled rectifier and the ground;

the relay drives the reset switch through a mechanical link;

the reverse connection detection control circuit comprises the microcontroller, a twenty-fourth capacitor, a fourteenth resistor, and a heavy and light current isolation optocoupler;

the twenty-fourth capacitor is connected between a third triggering terminal of the microcontroller and the ground;

the fourteenth resistor is connected between the third triggering terminal of the microcontroller and a triggering control terminal of the heavy and light current isolation optocoupler;

a power supply terminal of the heavy and light current isolation optocoupler is connected to the VCC;

a first output terminal of the heavy and light current isolation optocoupler is connected to the load output terminal of the live line;

the detection and execution circuit comprises a twenty-fifth capacitor, a twenty-sixth capacitor, a normally-closed contact, a normally-open contact, a seventh resistor, a normally-closed switch, and a reverse relay;

the twenty-fifth capacitor and the twenty-sixth capacitor are connected in series;

the twenty-fifth capacitor is connected with the normally-closed contact, the normally-open contact, a first terminal of the reverse relay, and a second output terminal of the heavy and light current isolation optocoupler;

the twenty-sixth capacitor is connected with the load output terminal of the live line;

the seventh resistor is connected between a connection point between the twenty-fifth and twenty sixth capacitors and a load output terminal of the neutral line;

the normally-closed switch is provided on the live and neutral lines between the load output terminals of the live and neutral lines and the reset switch;

the normally-closed switch is linked with the normally-open contact;

the second terminal of the reverse relay is connected to the load output terminal of the neutral line; and

the reverse relay drives the normally-closed switch through a mechanical link.

8. The protection circuit according to claim 7, wherein:

the control circuit of the tripping mechanism control circuit further comprises a third one-way silicon controlled rectifier;

the twelfth resistor is connected between the first triggering terminal of the microcontroller and a control electrode of the third one-way silicon controlled rectifier;

an anode of the third one-way silicon controlled rectifier is connected to the connection point where the inductor coil is connected to of the second input terminal of the first rectifier circuit; and

a cathode of the third one-way silicon controlled rectifier is grounded.

9. The protection circuit according to claim 7, wherein:

the power supply circuit comprises a piezoresistor and an over-current protection resistor;

the piezoresistor is connected between the input terminal of the live line and the input terminal of the neutral line;

the over-current protection resistor is connected between the input terminal of the live line and an input terminal of the power supply filter circuit.

10. The protection circuit according to claim 8, wherein:

the power supply circuit comprises a piezoresistor and an over-current protection resistor;

the piezoresistor is connected between the input terminal of the live line and the input terminal of the neutral line;

the over-current protection resistor is connected between the input terminal of the live line and an input terminal of the power supply filter circuit.

11. The protection circuit according to claim 3, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, a fifteenth resistor, a second one-way silicon controlled rectifier, and a sixteenth resistor;

the twenty-seventh capacitor is connected between ground and a second triggering terminal of the microcontroller;

the fifteenth resistor is connected between the second triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the sixteenth resistor are connected in series between the live line and the ground; and

the sixteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

12. The protection circuit according to claim 4, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, a fifteenth resistor, a second one-way silicon controlled rectifier, and a sixteenth resistor;

the twenty-seventh capacitor is connected between ground and a second triggering terminal of the microcontroller;

the fifteenth resistor is connected between the second triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the sixteenth resistor are connected in series between the live line and the ground; and

the sixteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

13. The protection circuit according to claim 5, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, a fifteenth resistor, a second one-way silicon controlled rectifier, and a sixteenth resistor;

the twenty-seventh capacitor is connected between ground and a second triggering terminal of the microcontroller;

the fifteenth resistor is connected between the second triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the sixteenth resistor are connected in series between the live line and the ground; and

the sixteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

14. The protection circuit according to claim 6, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, a fifteenth resistor, a second one-way silicon controlled rectifier, and a sixteenth resistor;

the twenty-seventh capacitor is connected between ground and a second triggering terminal of the microcontroller;

the fifteenth resistor is connected between the second triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the sixteenth resistor are connected in series between the live line and the ground; and

the sixteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

15. The protection circuit according to claim 7, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, a fifteenth resistor, a second one-way silicon controlled rectifier, and a sixteenth resistor;

the twenty-seventh capacitor is connected between ground and a second triggering terminal of the microcontroller;

the fifteenth resistor is connected between the second triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the sixteenth resistor are connected in series between the live line and the ground; and

the sixteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

16. The protection circuit according to claim 8, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, a fifteenth resistor, a second one-way silicon controlled rectifier, and a sixteenth resistor;

the twenty-seventh capacitor is connected between ground and a second triggering terminal of the microcontroller;

the fifteenth resistor is connected between the second triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the sixteenth resistor are connected in series between the live line and the ground; and

the sixteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

17. The protection circuit according to claim 9, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, a fifteenth resistor, a second one-way silicon controlled rectifier, and a sixteenth resistor;

the twenty-seventh capacitor is connected between ground and a second triggering terminal of the microcontroller;

the fifteenth resistor is connected between the second triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the sixteenth resistor are connected in series between the live line and the ground; and

the sixteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

18. The protection circuit according to claim 10, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, a fifteenth resistor, a second one-way silicon controlled rectifier, and a sixteenth resistor;

the twenty-seventh capacitor is connected between ground and a second triggering terminal of the microcontroller;

the fifteenth resistor is connected between the second triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the sixteenth resistor are connected in series between the live line and the ground; and

the sixteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

19. A ground fault circuit interrupter, comprising an interrupter body, wherein the interrupter body includes the protection circuit of claim 3.

20. A ground fault circuit interrupter, comprising an interrupter body, wherein the interrupter body includes the protection circuit of claim 7.